This invention generally relates to the art of electrical connectors and, particularly, to an electrical connector assembly for effecting a connection between two circuit boards.
A variety of electrical connectors have been used to make electrical connections between the circuits on different printed circuit boards. These printed circuit boards must be joined together with connectors in a manner to effectively and reliably interconnect the circuits on one circuit board to the circuits on another circuit board. This is done by a pair of mating connectors which are surface mount connectors and may include a male or plug connector mateable with a female or receptacle connector to form a board-to-board electrical connector assembly.
As stated above, both connectors of the electrical connector assembly are surface mount connectors. Both connectors typically have a low profile and have some form of mechanism to hold the connectors together. The holding mechanism preferably aligns the connectors, prevents the two connectors from wobbling and maintains the terminals of the connectors in good, positive interengagement.
Whatever holding mechanism is used to hold the connectors in mated condition, considerable constraints are placed on the design of the mechanism due to the very low profile of the connectors. For instance, mating posts may be used on one connector for insertion into mating passages of the other connector. The posts are press-fit into the passages and may be used to properly align the connectors. However, the passages extend into one of the connector housings only a limited distance which, in many instances, is insufficient to prevent the connectors from wobbling. This problem is further magnified if the mating posts are beveled. In other words, in order to facilitate blind mating of the connectors in most applications, the mating posts have beveled distal ends. This shortens the effective length of the posts which further causes problems in trying to prevent the connectors from wobbling and in trying to maintain a good, positive connection between the respective terminals. The present invention is directed to solving these various problems, particularly in a board-to-board electrical connector assembly wherein the respective connectors have very low profiles.
An object, therefore, of the invention is to provide a new and improved board-to-board electrical connector assembly for effecting a connection between two circuit boards.
In the exemplary embodiment of the invention, the connector assembly includes a first connector having a low profile dielectric housing including a mating face and a mounting face for mounting the connector on a first circuit board. A plurality of spaced mating posts project from the mating face of the housing. A plurality of first terminals are mounted on the dielectric housing and each terminal includes a tail portion for connection to an appropriate circuit trace on the first circuit board and a contact portion exposed generally at the mating face of the housing.
A second connector has a low profile dielectric housing including a mating face for mating with the mating face of the housing of the first connector, and a mounting face for mounting on a second circuit board. A plurality of mating passages are provided in the housing for receiving the mating posts of the first connector. The passages extend from the mating face to and through the mounting face of the dielectric housing of the second connector. A plurality of second terminals are mounted on the dielectric housing of the second connector. Each second terminal includes a tail portion for connection to an appropriate circuit trace on the second circuit board, and a contact portion for engaging the contact portion of one of the first terminals of the first connector.
The invention contemplates that the mating posts of the first connector be snugly fit in the mating passages of the second connector, with the mating posts extending all the way to the mounting face of the second connector to align the connectors, to prevent wobbling of the connectors and to maintain the contact portions of the terminals in engagement.
According to one aspect of the invention, the mating posts of the first connector have distal ends which are beveled to facilitate blind mating of the connectors. The distal ends of the mating posts are generally flush with the mounting face of the second connector when the connectors are mated.
According to another aspect of the invention, the dielectric housing of the first connector is generally rectangular and includes four of the mating posts generally at four corners of the housing. The first connector comprises a plug connector, and the second connector comprises a receptacle connector having a generally rectangular receptacle means having four of the mating passages at four corners of the receptacle means.
Other features of the invention include at least one of the mating posts and a corresponding mating passage being of a different size from another mating post and corresponding mating passage to provide a polarization means for the connector assembly. The dielectric housing of at least one of the connectors may include a plurality of terminal-mounting holes in the mating face of the housing, whereby the terminals are mounted to the housing through the mating face opposite the mounting face which is mounted to the respective circuit board.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.